1.特性是一个类,它继承于Attribute。它对程序中的元素进行标注，如类型、字段、方法和属性等。
Attribute是程序代码的一部分，它不会被编译器丢弃，而且还会被编译器编译进程序集（Assembly）的元数据（Metadata）里。
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property)] //表示该特性可以修饰字段，属性 、（Class、Method）可修饰类、方法
public class FieldForExportAttribute : Attribute
{
/// <summary>
/// 标记导出属性
/// </summary>
/// <param name="columnName">列名</param>
/// <param name="sort">排序</param>
/// <param name="tasktype">任务类型</param>
public FieldForExportAttribute(string columnName, int sort = 0, int tasktype = 0)
{
ColumnName = columnName;
Sort = sort;
TaskType = tasktype;
}
public string ColumnName { get; }
public int Sort { get; }
public int TaskType { get; }
}
2、新建类，给属性、字段标注
/// 我的业务页面使用的公共查询响应实体
/// </summary>
public class UtoClass
{
/// <summary>
/// 发起人id
/// </summary>
public string AccpetUserID { get; set; } //X
/// <summary>
/// 发起人姓名
/// </summary>
[FieldForExport("发起人",65)]
public string AppProposer { get; set; }
/// <summary>
/// 办结时间//结束流程的时间
/// </summary>
[FieldForExport("办结时间",50)]
public string EndedDateTime { get; set; }
/// <summary>
/// 当前环节ID/业务节点
/// </summary>
public string FunctionID { get; set; }
}
List<KeyValuePair<string, string>> keyValuePairs = new List<KeyValuePair<string, string>>();
var dt = GetTable(res, ref keyValuePairs,1);
/// <summary>
/// 返回的list数据转datatable
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="list"></param>
/// <param name="keyValuePairs"></param>
/// <param name="type">1.待办业务 2其他业务</param>
/// <returns></returns>
private DataTable GetTable<T>(List<T> list, ref List<KeyValuePair<string, string>> keyValuePairs,int taskType=0)
{
List<T> zz= list.OrderBy(x => x.GetType().GetProperty("name")).ToList();
var dt = new DataTable("Datas");
var type = typeof(T);
var propertyInfos = (from p in type.GetProperties()
let attr = p.GetCustomAttribute<FieldForExportAttribute>()
where attr != null
&& (attr.TaskType == 0 || attr.TaskType == taskType)
orderby attr.Sort descending
select p).ToList();
dt.Columns.Add(new DataColumn("序列号", typeof(string)));
keyValuePairs.Add(new KeyValuePair<string, string>("序列号", "序列号"));
foreach (var item in propertyInfos)
{
var a = item.GetCustomAttribute<FieldForExportAttribute>();
dt.Columns.Add(new DataColumn(a.ColumnName, typeof(string)));
keyValuePairs.Add(new KeyValuePair<string, string>(a.ColumnName, a.ColumnName));
}
var index = 1;
foreach (var item in list)
{
var dr = dt.NewRow();
dr["序列号"] = index;
foreach (var p in propertyInfos)
{
var a = p.GetCustomAttribute<FieldForExportAttribute>();
dr[a.ColumnName] = p.GetValue(item)?.ToString();
}
dt.Rows.Add(dr);
index++;
}
return dt;
}
